More commonly, non-traditional high temperature composite materials, such as ceramic matrix composite (CMC) materials, are being used in applications such as gas turbine engines. Components fabricated from CMC materials have a higher temperature capability compared with typical components, e.g., metal components, which may allow improved component performance and/or increased system temperatures. Generally, gas turbine engines include combustion sections in which compressed air is mixed with a fuel and ignited to generate high pressure, high temperature combustion gases that then flow downstream and expand to drive a turbine section coupled to a compressor section, a fan section, and/or a load device. Components within the gas flow must be adequately restrained to ensure the components remain in their proper location within the flowpath. However, typical attachment methods and assemblies often expose the structure for supporting and securing the flowpath components to relatively high temperatures, e.g., from relatively high pressure purge flow and the combustion gases. Often, the support structure comprises metallic components, which are less capable of withstanding high temperatures than CMC components and that have different coefficients of thermal expansion (CTE) than CMC components. Therefore, exposing the metallic support structure to the relatively high flowpath and purge flow temperatures risks overheating the metallic support structure and losing clamp load between the metallic support structure and CMC attachment assembly hardware, as well as other detrimental effects from the CTE mismatch between the metallic and CMC attachment hardware.
Accordingly, improved retention assemblies and cooling methods that protect the metallic support structure from relatively high purge flow and flowpath temperatures would be desirable. As an example, a retention assembly for securing CMC components to one or more metallic supporting components that utilizes a lower temperature cooling airflow passage and a separate higher temperature purge or cooling airflow passage would be beneficial.